third_party/WebKit/Source/modules/webdatabase/DatabaseTracker.h

/*
 * Copyright (C) 2007, 2008, 2013 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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 */

#ifndef DatabaseTracker_h
#define DatabaseTracker_h

#include <memory>
#include "modules/ModulesExport.h"
#include "modules/webdatabase/DatabaseError.h"
#include "platform/heap/Handle.h"
#include "platform/wtf/Functional.h"
#include "platform/wtf/HashMap.h"
#include "platform/wtf/HashSet.h"
#include "platform/wtf/ThreadingPrimitives.h"
#include "platform/wtf/text/StringHash.h"
#include "platform/wtf/text/WTFString.h"

namespace blink {

class Database;
class DatabaseContext;
class Page;
class SecurityOrigin;

class MODULES_EXPORT DatabaseTracker {
  WTF_MAKE_NONCOPYABLE(DatabaseTracker);
  USING_FAST_MALLOC(DatabaseTracker);

 public:
  static DatabaseTracker& Tracker();
  // This singleton will potentially be used from multiple worker threads and
  // the page's context thread simultaneously.  To keep this safe, it's
  // currently using 4 locks.  In order to avoid deadlock when taking multiple
  // locks, you must take them in the correct order:
  // m_databaseGuard before quotaManager if both locks are needed.
  // m_openDatabaseMapGuard before quotaManager if both locks are needed.
  // m_databaseGuard and m_openDatabaseMapGuard currently don't overlap.
  // notificationMutex() is currently independent of the other locks.

  bool CanEstablishDatabase(DatabaseContext*,
                            const String& name,
                            const String& display_name,
                            unsigned estimated_size,
                            DatabaseError&);
  String FullPathForDatabase(SecurityOrigin*,
                             const String& name,
                             bool create_if_does_not_exist = true);

  void AddOpenDatabase(Database*);
  void RemoveOpenDatabase(Database*);

  unsigned long long GetMaxSizeForDatabase(const Database*);

  void CloseDatabasesImmediately(SecurityOrigin*, const String& name);

  using DatabaseCallback = Function<void(Database*)>;
  void ForEachOpenDatabaseInPage(Page*, std::unique_ptr<DatabaseCallback>);

  void PrepareToOpenDatabase(Database*);
  void FailedToOpenDatabase(Database*);

 private:
  using DatabaseSet = HashSet<CrossThreadPersistent<Database>>;
  using DatabaseNameMap = HashMap<String, DatabaseSet*>;
  using DatabaseOriginMap = HashMap<String, DatabaseNameMap*>;

  DatabaseTracker();

  void CloseOneDatabaseImmediately(const String& origin_identifier,
                                   const String& name,
                                   Database*);

  Mutex open_database_map_guard_;

  mutable std::unique_ptr<DatabaseOriginMap> open_database_map_;
};

}  // namespace blink

#endif  // DatabaseTracker_h